Loads of possible faults cause the Glow Plug Error message to come up... Which depending on what you're using to read the codes might not show up...

Not to worry though, the error code message is pretty useless! Just says there's a problem with the Glow Plug system... So could be fuse, relays, glow plugs, wiring etc....

Got a multi-meter? Quick and easy check to check the resistance between the plug and ground to spot a obviously faulty plug!

Where in Devon are you? I've got 3 spare plugs and a relay module on the spare parts shelf in the garage! Worthwhile doing some fault finding first though... Might be nothing wrong with the kit you've got!

My 156 flashes glow plugs with no fault code stored. I've not investigated as it is still a good starter even when cold. If the dash warnings bother you then new glow plugs are pretty cheap and all being well are easily removed with a deep socket (9mm maybe 11mm or 8mm can't remember).

Lifted the engine cover, pulled off the glow plug leads set about measuring the glow plug resistance. It soon became evident that glow plug for cylinder No1 was the culprit. Eventually found a deep 9mm socket, warmed the engine up and sprayed penetrating oil everywhere. Braced myself for a fight to get the plug out and yes you guessed it - it was only done up finger tight!!!! Fitted new one any way and now enjoying beep free driving.